Add external link style for alt. protocols

Author: jordanmccullough

_stylesheets/workbook.scss

@@ -19,7 +19,8 @@
 
 .workbook{
 /* General external link */
-a[href^="http://"]{
+a[href^="http://"],
+a[href^="https://"]{
 @includeocticon-link("\f0b6");
  }